This invention relates to tubular elastomeric springs, and, more particularly to tubular elastomeric springs which provide both constant and rising spring rates. As used herein, the term "breakover" means the change in spring deflection from constant to rising rate.
Cylindrical elastomeric springs typically provide only constant rate or rising rate deflection, not both. Those cylindrical elastomeric springs which provide both constant and rising rate deflection, moreover, have unsatisfactory breakovers. These springs therefore tend to be unacceptable for applications which require rising rate performance above a certain load and constant rate performance below it.
Such applications typically involve lightweight passenger vehicles, for example, in which hood height requirements, suspension strut lengths, and other environmental factors effectively limit the operational length of the spring. In order to meet these requirements, yet provide the requisite load bearing capacity, the spring often has to be constructed with such thick walls that it has no breakover at all. Consequently, the performance versatility which could have been obtained from having both constant and rising rate performance is lost.